Vacuum insulating panels are used conventionally for thermal insulation. Known vacuum insulating panels consist of a pre-compressed porous filling, a porous pressboard or an open-cell rigid foam as substrate, which is enveloped by a gas-tight film, wherein the film is heat-seated or bonded after the evacuation.
The following, for example, are used as filling materials for vacuum insulating panels: precipitated and dried silicas, silica gels, fly ash, open-cell foams on an organic base such as open-cell rigid polyurethane foams or bonded rigid polyurethane foam paste, which are described in DE 4,439,331 and DE 4,439,328.
Vacuum insulating panels of this type are used in the manufacture of cold rooms, e.g., refrigerators or refrigerated containers, with the latter being inserted between the outer and inner casing and the gap left between the outer and inner casing being filled with foam.
The fitting of the vacuum insulation panels into refrigerator casings nevertheless presents problems. According to the current state of the art, they are bonded onto a plate--for example, a metal cassette--by means of a double-sided adhesive film. This combination plate can then be processed further into a sandwich panel, for example, a refrigerator door, wherein the cavity left is conventionally filled with foam.
As a result, on the one hand, a complicated, multi-step process is required, and on the other hand, the insulation volume is affected by the foam, which is less efficient in insulation terms when compared with a vacuum insulation panel. Arrangements of this type are also, to only a limited extent, without thermal bridges.
These disadvantages can be prevented if the vacuum insulation panel is fixed with a polyurethane foam strip, which is applied as a liquid reaction mixture--preferably peripherally--at the edge of the vacuum insulation panel on the rigid top layer or between two rigid top layers.